Measuring Excess Nutrients

 

Background

 

Phosphorus (P) is an essential nutrient for plant growth and animal metabolism. Plant growth depends on the amount of P available. In some areas P is present in very low concentrations, so it is a growth limiting factor. Nitrogen(N) is another essential nutrient. Plants and animals use N to build proteins. Plants absorb N through their roots and use it to make plant proteins, which are then converted to animal protein when animals the plants. N is usually more available for use than P, because it is found in water in different forms: molecular nitrogen(NO3); ammonia (NH3);a product of animal wastes and the decay of animal proteins; and nitrate (NO3) and nitrite (NO2)which are formed when specialized bacteria combine ammonia with oxygen.Although N and P are necessary nutrients, too much of them in the water causes pollution. Algae use up P very quickly. Excess P encourages vast growth algae (algal bloom), which makes the water look like pea soup. Algal blooms use up a great deal of DO which causes anoxic conditions. Too much N (ammonia and nitrates) causes similar problems. This excessive nutrient enrichment of water can cause eutrophication (aging of a lake or wetland). Nutrients enter water during natural events or human activity. Organic P and N are present in living pant and animal tissues, and become organic matter when the organisms die. The natural weathering of rocks and soil transports minerals and nutrients. Percipitation and snow melt increase runoff that carries nutrients and pollutants to waterways. Ground water flow and streams and rivers carry nutrients from place to place. This natural transport of materials helps supply plants and animals with needed nutrients. However, a variety of human activities can send excess nutrients into an ecosystem. Human and other animal wastes enter waterways through wastewater treatment plants and agricultual runoff. Disturbance of the land and its vegetation adds excess nutrients that are normally held in its soil. Erosion is speeded up by these activities, so that soil and its accompanying nutrients end up in the water. Nutrients stored in wetlands are released into waterways when wetlands are drained for development. Wetlands filter and trap ecxess nutrients and their pollutants before they can enter waterways/. Wetland plants use up many of the excess nutrients that run off the land. Wetlands work to keep things in balance in the water.

 

Materials

 

Nitrogen and phosphorus